The 30-year-old plays The Mountain in the HBO hit series, which returns to screens this weekend for the highly-anticipated eighth season.
Björnsson triumphed at the competition in Leeds, paying tribute to his support team and revealing his Icelandic pride.
He said: “Europe’s Strongest Man for the fifth time! So blessed to have such great people behind me! Team Iceland baby.
“Huge thank you to all my family, my beautiful wife and all my friends for all the help and support!!”
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Björnsson dead-lifted an astonishing 770 lbs, performing 10 repetitions to triumph.
He also performed the log lift challenge, the tyre flip, an Atlas stone lift, and then the ‘pillars of Hercules’, whereby the strongman holds two chains in order to prevent two 350-pound-plus pillars from falling over.
Hafþór Júlíus Björnsson at the Game of Thrones premiere (Instagram/thorbjornsson )
(Instagram/thorbjornsson)
Poland’s Mateusz Kieleszkowski and Georgia’s Konstantine Janashia came in second and third.
Björnsson reveals his success is fuelled by consuming 10,000 calories per day.
Bjornsson shone in the deadlift (Instagram/thorbjornsson )
(Instagram/thorbjornsson)
“I can lift 1,000 pounds, and I eat 10,000 calories a day,” he reveals to Page Six.
“I have to eat every two hours to maintain myself.”
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